Piston



1932. E. s. REILAND ET AL 1,885,290

PISTON Filed Sept. 6, 1929 Qwomto'o [772652 :5: fieizdrlaFeY'GPJCZZeiZanZ Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE fERNEST s. REILAND AND rn'rna M:REILA 1\TD, OF s1. PAUL, MINNESOTA,assIoNOns'ro UNIVERSAL PISTON COMPANY, OF s1. PAUL, MINNESOTA, A,CORPORATION OF MIN- NESOTA PIsToN Application filed September 6, 1929.Serial NO. 390,724. 7

Our invention relates to lightweight pistons particularly a piston madeof aluminum alloyor of any other lightweight material of a similarnature wherein it is desired to pro vide a piston which will operate tomaintain the compression rings in proper position and where the pistonmay act as the core to support the same and including a means forholding the piston centrally in the cylinder and against piston slapunder any condition in the operation of the same.

A feature of the invention resides in a peculiar means for supportingthe piston in the cylinder in a manner so that a more eflicientcompression may be maintained particularly in high compression internalcombustion engines, or in any internal combustion engine, all of whichis accomplished by the means of supporting the piston within thecylinder.

Our invention further includes a means for holding the piston so thatthe major force of the explosion on one side of the same, as isprevalent in high'compressioninternal combustion engines, is overcome orprevented from affecting the pistonto cause it to be driven to one sideOf the cylinder or to be tipped in the cylinder in its operation. Thiswe accomplish with a particular means which is'a-daptable tocompensatefor inequalities, wear and expansion and contraction. Ourmeans of supporting the piston is such as to give a better compressionin the cylinder and to largely overcome blow-by and thus prevent oildilution which is so detrimental in internal combustion engines. 7

A furtherfeature of our invention resldes in means for supporting thepiston inthe' cylinder with a large clearance, thus permitting thepiston to be made without a split skirt or of a shell-like nature andyet with virtually a minimum of wall frictionowing to the nature of thesupports for the piston. Our piston has a great deal, less wall frictionbecause it has a lesser area engaging with the cylinder wall. In thismeans of supporting or holding the piston as will 'beomore fullyhereinafter setforth, we maintain a cylindrical-like oil film about theskirt which lubricates the cylinder walls and rings of the piston 1n avery desirable manner. Thls O11 film is highly important as it not onlylubricates the cylinder wall but it assists in maintaining a sealannularly or virtually cylindrical'ly about thepiston.

The features of our invention and objects,

together with the advantages and the particular construction and themeans of carrying out the same will be more fully and clearly set forth.i

In the drawingiorming part of this specifitive construction of ourpiston.

In the drawing our piston A is illustrated with a thin wall at the skirtportion 10, whilethe head portion 11 is adapted to be formed 'with'theusual recesses 12 for the'piston compression rings. The-head 11 is alsoformed with an oil groove ring 13. Our piston A is designed to be madeof aluminum Or-aluminum alloy 01' any lightweight material and isconstructed of the solid type ratherthan of the split skirt type. Thissolid type structureprovides a cylindrical body from the head andthrough the skirt of the piston and :ow'ing tothe fact that aluminum orsimilar lightweightmaterial has a different cxpandingnature than thatofiron or steel, such as is'used in cylinder blocks and sleeves, it isessential that our piston A be made smaller in diameter than thediameter of the cylinder in which the piston is designed to operate;VVe-have found' th-at by particular supporting means such as B and C forthe piston, that we successfullyoperate our piston to maint'aln thedesired compression within the combustion chamber D, indicated diaigrammatically bythe dotted outline, with the body or skirt of our pistonfrom eight to fifteen thousandths smaller than the di ameter of thecylinder which is indicated diagrammatically by the dotted lines in Figure 1. In fact, our piston may have a greater clearance than evenfifteen thousandths, if it is desired, and yet have no appreciable lossof compression owing to the structure of our piston supporting means 13and C.

A further important feature of the supporting of our piston A which isdesigned to be made of lightweight material is in the fact that it maybe made sufiiciently small in diameter to prevent the piston fromengaging with the wall of the cylinder and in maintaining acylindrical-like film .of oil between the piston supports B and Cvirtually at all times during the running of the piston and we havefound that this struetureprovides a piston which may be placed in aninternal combustion engine and the engine may be immediately run at anyspeed without injury to the pistons or the cylinder walls. This is anextremely valuable and important feature of our piston because itpermits the use of our pistons in automobiles and instead of the driverbeing cautioned not to drive over a certain speed until the motor is runin, we have found that virtually no harm or damage can be done to eitherthe pistons or the cylinders no matter at what speed the automobile isdriven. The lubricating by the main tained cylindrical film of oil notonly accomplishes the advantages of lubrication for the cylinder wallsbut also to the rings and to assist in maintaining a flexible sealingmedium about the skirt spaced away from the head in such a manner as notto be infiuenced by the carbon formation in the combustion chamber D.

The supporting means B and C are of the same general structure exceptingas to certain reversal of parts as will be set forth. In the support Bwe provide a bearing ring 14L which is formed with beveled surfaces 15and 16 on either side of the same, the degree of bevel being varied tothe desired extent. The bearing ring 14 is adapted to be supportedagainst a beveled surface 17 formed in the head of the piston and with aportion of the arcuated inner surface 18 of thering 14bearing againstthe oomplemental arcuated shoulder 19 formed in the recess in the pistonhead which receives the ring 14;. The shoulder 19 extends in an arcuatedformation for a certain distance within the recess which receives thering 1 1 while the remainder of the recess is cut away as indicated inFigure 2 and also in Figure 1, so as to form a space 20 back of the ring14 for a distance greater than the semi-circumference of the ring 14.

The ring 14 is made preferably of a cylinder wall diameter, that is, theouter bearing surface 22 of the same is of a cylinder wall diameter, andthe ring 14: is held in position by a con'ipensating spring ring 23which is formed with a beveled surface adapted to engage against thebeveled surface 16 of the ring 14;.

To further assist the compensating ring 23 in supporting the ring ll inthe desired position and to maintain the piston A properly positionedwithin the cylinder of the internal combustion engine, we provide one ormore coil springs 2 1 which are positioned in suit- 'able recesses 25 ina manner U0 bear against the compensating ring 23. However, those coilsprings 24: do not bear against the bearing ring 14 but against theinner surface of the compensating ring 23. The spring members 2 1 arepositioned oppositely to the shoulder 19. This is an important structureof our piston A and it will be noted that this structure holds the ringlso that the back of the ring 1 1 will engage against the shoulder 19 andwhen explosive force from the combus tion chamber is exhausted againstthe head of the piston as indicated by the arrow 26 in Figure 1, thepiston is estopped from rotating on its pivot point 27 (the wrist pin)and thus the piston cannot slap at the head.

It has been stated that the parts of the support C are reversed as tothe same parts of the support B, however, the support C is of the samenature as the support B and the bearin ring 14 of the same is adapted tobe supported by the arctated shoulder 19 back of the ring 1 1. Theseparts in the support C function. exactly the same as the parts of thesupport B and the support C is provided with springs 24 held in therecesses 25. It will be noted that the, shoulders 19 and 19 arepositioned virtually diametrically opposite each other as are also thesprings 24 and 2 1. This structure provides a particular function in thesupporting of our piston A. o have stated that the force of theexplosion in the combustion chamber D at a point near the arrow 26 wouldnot carry the head of the piston 11 over against the wal of the cylinderand cause the same to slap and to assist in accomplishing this result inpreventing the piston from rotating on the pivot point 27 (wrist pin)the shoulder 19' is positioned opposite the shoulder 19. Thus theshoulder 19 in the skirt 10 of the piston holds the skirt of the pistonagainst movement toward the wall adjacent the shredder 19 in thedirection of the arrow 28, Figure 1. The spring rings 23 and 23 whichare the compensating rings of the two supports B and C for our piston Atogether with the spring means 2 1 and 24 compensate for any wear orinequalities in the parts and mainta in a sealed or tight fit betweenthe beveled surfaces 15 and 16 of the bearing rings 14- and 14:. In thismanner we provide a means of supporting the piston A centrally withinthe cylinder, yet with sufficient flexibility for wear and expansion andcontraction and at the same time provide a means for maintaining thedesired compression within. the combustion chamber so that in aninternal combustion engine Where several cylinders are employed thecombustion may be maintainedvirtually uniform within all of thecylinders. The beveled joints between the rings of the supports B and Cand the piston assist in forming a sealing joint together with the oilfilm between the bearings B and C which is of a cylindrical nature so asto accomplish the results hereinbefore set forth and permit the piston Ato be run at high speed without injury thereto or to the coils of thecylinder in which the piston is operating. i r

The grooves 12 support the ordinary compression rings and these ringsassist in holding the compression and also in keeping the bearings B andC clean of-carbon formation,

thus facilitating the free and proper opera-- tion of the bearings B andG to maintain the piston freely operable inthe cylinder.

In Figure 4 we have illustrated a series of coil springs 30, 31, 32',33, 34: and 35 which function similarly to the coil springs 2 by reasonof the fact that these springs operate against the compensating ring 23.The springs 33 and 34 are positioned opposite to the shoulder 19, inthis figure and these springs 33 and 34 are compressed greater than theremaining springs 30, 31, 32 and 35, to provide a greater pressure onthat side of the compensating ring 23 than on the other side.

Obviously, it is not essential that the pistons be equipped with thecoil springs 24 as the compensating sprin ring 23 may operate to performthe desired function in holding the bearing ring in its proper operatingposition. While it may be preferred to use the coil springs in somecases, we do not desire to be limited to their use because we know thatour compensating bearin g rings'for our piston will operate to supportthe same'with or without these coil springs. The features of preventingthe rotation of the piston readily carried out by our piston supportingmeans in the cylinder and thus we overcome side swiping of the piston orpiston clearance slap in the operation of the same.

It will be apparent that our piston A may be operated in anycylinder ofan internal combustion engine, either where the same is of a highcompressiontype with the combustion chamber enlarged to one side of thepiston, as illustrated diagrammatically in-dotted outline in Figure 1,or with the combustion chamber arranged centrally above the piston. I

The operation ofour piston has been set forth and includes thesupporting of the lightweight piston by the supporting means whichcompensate for expansion and contraction and which are designed withstop means onopposite sides of the piston whicheliminates rotation ofthe piston on its pivot 27*- impossible to secure'a piston slap and atno time does the piston body engage the wall of the cylinder; Thus weovercome the detrimental side thrusting'eifect of the connecting rod atthe wrist pin and owingto the rotary movement of the bearing rings 14;in their operation which we have observed in the'operation of ourpiston, we believe that wemaintain the wear of the cylinder round.instead of elliptical, therebyaccomplishing a very'desirable result. 1

In accordance with the patent statutes we have described the principalfeatures and construction of our piston and we have ondeavored torepresent the best embodiment thereof, setting forth some of the uses ofthe same, nevertheless, other features and ad vantages will be apparentas Well as other uses or forms of construction within the scope of thefollowing claims.

1 We claim:

.1. A piston including, a body portion, a wrist pin connection therein,bearing means for said'body portion on either side of said wrist pinconnection, said bearing means including a bearing ring, a springcompensat-v ing ring,: and a shoulder back of and con tacting with saidbearing ring formed in said piston.

2. A piston support including, a bearing ring, a spring compensatingring adapted to hold said-bearing ring in contact with said;

piston. and the Walls of the cylinder, and an arcuate'd shoulder formedin said piston back of said bearing ring against which said hearing ringis adapted to engage to space said piston away from the Wall ofsaidcylinder on one side of said piston.

3. A I piston including, a body portion, a head portion, a skirtportion, a wrist pin connection in the body portion, supporting means oneither side of saidwrist pin connection including a bearing ring,.aspring compensatingring, a shoulder back of said hearing ring on. onesideof said piston, and a space back of said bearing ring on the otherside thereof, the shoulder of one of said supporting means beingpositioned diametrically opposite to the shoulderof said supportingmeans positioned on eitherside of said Wrist pin connection preventingrotation of the piston about the wrist pin connection in its oporation.

4. A piston formed of aluminum and alloy comprising, a body portionhaving an undivided skirt, a wrist pin connection, bearing means oneither side of said Wrist pin connection having the parts of each ofsaid bearing means reversed as to position, each bearing means includinga bearing ring adapted to engage the cylinder wall, a beveled surface toengage the piston, a compensating spring ring, con'iplemental engagingbeveled surfaces on said compensating ring and said bearing ring, ashoulder back of said bearing ring on one side and adapted to engage thesame formed in said piston, and an open space on the other side, therebyproviding oppositely disposed shoulders in said piston to permit thebearing ring to form a SlIiiuCGl between the cylinder wall and thepiston to space the piston away from the wall of the cylinder.

5. A piston including, a body portion made of lightweight material, saidbody portion having means for supporting the compression rings, bearingcompensating ring means supported by said body portion having shouldermeans to )I'QVOIlt the rocking of the piston in its operation, means forspacing a greater portion of the bearing ring from said body and meansfor spacing the piston away from the wall of the cylinder so that at notime does the piston touch the walls of the cylinder.

6. A piston including, a body portion adapted to form the core tosupport the compression rings in a cylinder, wrist gin connection meansin said piston, compensating bearing rings positioned on either side ofsaid wrist pin and shoulder means formed in said piston back of saidcompensating bearing rings, positioned diametrically opposite the axisof the wrist pin connection, whereby the piston is supported againstrotation on the wrist pin connection.

7. A piston including, a body portion adapted to support in the head thecompression rings, a wrist pin connection in said piston, bearing ringspositioned on either side of the wrist pin connection adapted to spacethe piston from the wall of the cylinder, compensating means associatedwith said bearing ring to compensate for the expansion and contractionof the piston and the wear of said bearing rings and shoulder meanscooperating With said bearing rings and piston and positioneddiametrically opposite the pivotal axis of the wrist pin connection toprevent rotation of the piston on the axis of the wrist pin connection.

8. A piston including, a body portion having ring grooves for thecompression rings, a wrist pin connection for the connecting rod,bearing rings positioned on either side of said wrist pin connection andsupported by said piston, a shoulder back of each of said bearing ringson one side of said piston and a space back of said bearing rings on theother side of said piston, a resilient compensating ring co-aeting withsaid bearing ring to hold the bearing ring in operative posi-- tion andresilient means engageable with said compensating ring on the side ofthe piston opposite to said shoulder means.

9. A piston including, a body portion, a head for receiving thecompression rin s, a wrist pin connection in said body portion, abearing ring positioned on either side of said wrist pin connectionadapted'to support said piston in a cylinder, an arcuated shoulderportion formed to cooperate between the backof said bearing ring andsaid body of said piston on one side of said piston and an arcuated opengroove back of the remaining portion of said bearing ring and piston.

10. in apiston provided with bearing ring grooves above and below thewrist pin axis thereof, a shoulder formed on the wall of each of saidgrooves, said shoulders being arranged on diametrically opposite sidesof the piston, one in each of the respective grooves, bearing rings insaid grooves having limited portions thereof in contact with. saidshoulders, and means also carried in said grooves retaining said ringsin contact with said shoulders and in contact with the walls of acylinder when the piston is inserted in the latter.

11. In a piston provided with a bearing ring groove having an arcuateshoulder formed therein on one side of the wrist pin axis, a bearingring engaging said shoulder, a compensating ring and means for exertinga preponderance of radial pressure on said compensating ring to seatsaid bearing ring on said shoulder and hold the same in contact with acylinder wall.

12. In a piston provided with a bearing ring groove having an arcuateshoulder formed therein. on one side of the wrist pin axis, a bearingring engaging said shoulder, a compensating ring and means for exertinga preponderance of radial pressure on said compensating ring at a pointdiametrically opposite said shoulder to seat said bearing ring on saidshoulder and hold the same in contact with a cylinder wall. v

13. In a piston provided with a bearing ring groove having an arcuateshoulder formed therein on one side of the wrist pin axis, a bearingring engaging said shoulder, a compensating ring in contact with saidhearing ring, the contacting faces of said bearing and compensatingrings being evelled on the same angle, and means for exertingpreponderance of radial pressure on said compensating ring to saidbearing ring on said shoulder and hold the same in contact with acylinder Wall.

4. Seth;

14:. In a piston provided with a bearing ring groove having an arcuateshoulder formed therein on one side of the wrist pin axis, a bearingring engaging said shoulder, a compensating ring incontact with saidbearing ring, the contacting faces of said bearing and compensatingrings being bevelled on the same angle, and means for exerting apreponderance of radial pressure on said compensating ring at a pointdiametrically opposite the said shoulder to seat said bearing ring onsaid shoulder and hold the same in contact with a 7 cylinder wall.

15. In a piston including top and skirt portions on opposite sides ofthe wrist pin axis,

said top and skirt portions being each formed with a bearing ring grooveand each groove having a shoulder formed on a Wall thereof to one sideof the wrist pin axis, said shoulders being arranged on diametricallyopposite sides of the piston, a bearing ring in each groove engaging therespective shoulder I thereof, a compensating ring in each groove andmeans for exerting a preponderance of radial pressure on eachcompensating ring to seat the adjacent bearing ring on the adjacentshoulder and hold the same in contact with the cylinder wall.

16. In a piston including top and skirt portions on opposite sidesof thewrist pin axis,

said top and skirt portions being each formed with a bearing ring grooveand each groove having a shoulder formed on a wall thereof to one sldeof the wrist pin axis, sald shoulders being arranged on dlametricallyopposite sides of the piston, a bearing ring in each groove engaging therespective shoulder thereof, a compensating ring in each groove, andmeans arranged at a point diametrically opposite the shoulder in eachgroove for exerting a preponderance of radial pressure on thecompensating ring of the adjacent groove to seat the bearing ringthereof on the adjacent shoulder and hold the same in contact with thecylinder wall. 7

ERNEST S. REILAND. PETER M. REILAND.

